The present invention relates to a buckles for use in safety belt device, such as seat belt device, mounted on a seat of a vehicle, such as automobile.
Recently, on the seats of various types of vehicles, typically automobiles, seat belt devices are mounted to protect the vehicle occupants in case of emergencies, such as collisions. In order to readily fasten and unfasten the seat belt device of this type, normally there is provided a buckle which includes a latch member having a joggle unit for latching a tongue, the latch member being biased by a spring in a direction which allows latching of the tongue.
When the tongue is inserted from a tongue insertion hole of the buckle, the tip of the tongue is led inside by guide units provided on two side walls of a base of the buckle.
FIG. 7 is a schematic view of a conventional guide unit.
As shown in FIG. 7, on two side walls 71a of a base 71, guide units 72 are formed to protrude inward. As for each guide unit 72, the guide unit 72 leads the tip of a tongue 73 when the tongue 73 is inserted.
However, in this conventional buckle, the guide unit 72 is formed to be relatively short in the longitudinal direction. Thus, as shown by a two-dot chain line in FIG. 7, when the tongue 73 is inserted in a highly slanted manner relative to the buckle, the tip of the tongue 73 is sometimes caught on the edges of the guide units 72 to prevent a smooth insertion. Consequently, in the conventional buckle, the manipulation feeling for inserting the tongue 73 was not always satisfactory.
The present invention has been made in view of the problems, and an object of the invention is to provide a buckle which allows a smoother insertion of the tongue so that the manipulation feeling for insertion is significantly improved.
In order to solve the above-described problems, a buckle in a first aspect according to the present invention includes a base having two side walls, a cover for accommodating and supporting the base, and a tongue insertion hole formed in the cover at one end side of the two side walls of the base. The buckle includes guide portions for leading a tongue inserted through the tongue insertion hole, provided on each of the two side walls so as to protrude inward relative to the two side walls. The guide portion leads the tip of the tongue without abutting against the guide portion even when the tongue is inserted from the tongue insertion hole in the maximally slanted manner defined by the tongue insertion hole relative to the buckle.
In the invention according to a second aspect, the buckle further includes operation means for unlatching the tongue and the buckle. A part of the operation means overlaps a part of the guide portion in a longitudinal direction, and the part of the operation means leads the tip of the tongue to the guide portion when the tongue is inserted into the buckle from the tongue insertion hole.
As for the buckle according to the invention having the above-described construction, even when the tongue is inserted from the tongue insertion hole in a slanted manner relative to the longitudinal direction of the buckle, the tip of the tongue is prevented from abutting against the edges of the guide units and is securely led by the guide part to achieve the smooth insertion. The manipulation feeling for inserting the tongue is effectively improved since the vehicle occupant, when seated, is most likely to insert the tongue into the buckle in such a slanted manner.
Especially for the buckle according to the second aspect, because the part of the operation means overlaps the part of the guide portion in a longitudinal direction, the tip of the tongue is securely led by the two side walls serving as the operation means without abutting against the edge of the guide portion, further effectively improving the manipulation feeling for inserting the tongue.